Abstract
The efficacy of the bio-insecticide,
Bacillus thuringiensis
var.
israelensis
(
Bti
), and four plant-ethanol extracts
Cinnamomum osmophloeum
,
Matricaria chamomilla
,
Seasamum indicum
, and
Nigella sativa
was tested against larvae of filarial vector,
Culex quinquefasciatus
, under laboratory conditions. The
Bti
and extracts of
N
.
sativa
and
C
.
osmophloeum
showed the highest insecticidal activity, with LC
50
values of 7.18, 14.59, and 28.87 mg/l 24 and 48 h post treatments, respectively. The extracts of
M
.
chamomilla
and
S
.
indicum
were effective. The tested extracts altered some biological aspects of
Cx
.
quinquefasciatus
, i.e., developmental periods, pupation rate, and adult emergence. Pupation rate was suppressed by
Bti
at 7.5 mg/l and by
C
.
osmophloeum
at 75 mg/l. In addition, the tested plant extracts exhibited various morphological abnormalities of larvae, pupae, and adults.